Method for annealing a semiconductor

ABSTRACT

A method for manufacturing a semiconductor device including preparing a multi-chamber system having at least first and second chambers, the first chamber for forming a film and the second chamber for processing an object with a laser light; processing a substrate in one of the first and second chambers; transferring the substrate to the other one of the first and second chambers; and processing the substrate in the other one of the chambers, wherein the first and second chambers can be isolated from one another by using a gate valve.

REFERENCE TO RELATED APPLICATION

This application is a Divisional of application Ser. No. 08/721,540filed Sep. 26, 1996 now U.S. Pat. No. 6,174,374; which itself is aDivisional of Ser. No. 08/275,909 filed Jul. 15, 1994, now U.S. Pat. No.5,578,520; which is a CIP of Ser. No. 08/104,614 filed Aug. 11, 1993,now U.S. Pat. No. 5,352,291 (which has been reexamined and issued asU.S. Pat. No. B15,352,291); which is a Continuation of Ser. No.07/886,817 filed May 22, 1992, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for annealing a semiconductor,in particular, to an annealing process for obtaining a polycrystalsemiconductor used in a thin film device such as an insulated gate fieldeffect transistor by laser irradiation.

2. Description of Prior Art

Thin films of polycrystalline silicon semiconductor for use in a thinfilm device such as a thin film insulated gate field effect transistor(abbreviated hereinafter as a TFT) have been fabricated heretofore byfirst depositing amorphous silicon films by plasma-assisted chemicalvapor deposition (CVD) or thermal CVD processes, and then irradiating alaser beam thereto to crystallize the thus deposited amorphous siliconfilms.

The process of crystallizing an amorphous silicon film by irradiating alaser beam comprises, in general, first irradiating a low energy densitylaser beam to the amorphous silicon film to allow desorption of hydrogenhaving incorporated into the starting amorphous silicon film, and thenirradiating a laser beam at an energy density well above the thresholdenergy density (a minimum energy density necessary to initiate meltingof silicon).

A laser beam having a sufficiently low energy should be irradiated tothe amorphous silicon film for the purpose of releasing the hydrogenbeing incorporated in the film because, if a beam of a high energydensity corresponding to the threshold value or higher were to beirradiated, there occur two problems. One is a problem which involvesabrupt evolution of a considerable amount of hydrogen from the surfaceof an amorphous silicon film upon irradiating the laser beam. Such aphenomenon greatly impairs the smoothness of the film surface; theresulting film cannot provide a favorable interface level when aninsulator film is established on the surface of the thus crystallizedsilicon film, because a level develops at the interface between thesilicon film and the insulator film. The other problem is the hydrogenspresent in large amount in the amorphous silicon film; they not onlyevolve out of the surface upon irradiation of a high energy laser beamhaving an energy density not lower than the threshold value, but alsomove inside the melting silicon film with a large kinetic energy toimpede the crystallization of the silicon itself.

Accordingly, a conventional laser annealing processes involves aso-called pre-laser annealing step which comprises irradiating a lowenergy density laser beam to sufficiently drive out hydrogen atomshaving incorporated inside the film, followed by the irradiation of alaser beam having a satisfactorily high energy density to effectcrystallization of the film. In this manner, the influence of thehydrogen inside the film on the film crystallization can be eliminated.

The conventional laser annealing processes, however, sufferdisadvantages as follows.

Firstly, the laser annealing process should be conducted in two steps.Such a process is not suitable for processing large-area substrates.Moreover, it suffers poor efficiency.

Secondly, the most generally used excimer lasers which are operated in apulsed mode are not suitable for completely driving hydrogen out of thefilm; the duration of the laser irradiation per pulse is too short.

Furthermore, any laser apparatus for use in the laser annealinginevitably suffers a non-uniform laser beam output and a fluctuation inpower output. Those attributes make the hydrogen distributionnon-uniform inside the film upon driving hydrogen atoms out of the film.Such a film having a non-uniform hydrogen distribution therein resultsin a crystallized film consisting of crystal grains of non-uniform graindiameter.

SUMMARY OF THE INVENTION

The present invention relates to a laser annealing process havingovercome the aforementioned problems.

More specifically, the present invention provides a method for annealinga semiconductor comprising the steps of:

thermally annealing an amorphous semiconductor in vacuum or inactiveatmosphere at a temperature not higher than a crystallizationtemperature of said amorphous semiconductor; and

irradiating said amorphous semiconductor with a laser light in vacuum orinactive atmosphere after said thermally annealing step to crystallizesaid amorphous semiconductor.

The laser to be used in the process in general is an excimer laser, butit should be noted that the construction of the present invention is byno means restricted to the use thereof, and hence, any type of laser canbe employed in the process.

The generally used amorphous semiconductor, but not limiting, is asilicon semiconductor. In the description of the present inventionhereinafter, however, a silicon semiconductor is used for purpose ofexplanation.

The thermal annealing of the amorphous semiconductor in vacuum or in aninactive gas atmosphere at a temperature not higher than thecrystallization temperature of said amorphous semiconductor is conductedfor the purpose of driving hydrogen oat of the amorphous semiconductor.If this step of thermal annealing were to be conducted at a temperaturenot lower than the crystallization temperature of the amorphoussemiconductor, crystallization would occur on the semiconductor, therebymaking the subsequent crystallization by laser irradiation insufficient.Accordingly, it is an important point that the thermal annealing isconducted at a temperature not higher than the crystallizationtemperature of the semiconductor.

The thermal annealing step should be effected in vacuum or in aninactive gas atmosphere to avoid formation of an undesirable thin film,such as an oxide film, on the surface of the amorphous semiconductor.

Hydrogen can be uniformly and thoroughly driven out of the film byannealing the amorphous semiconductor at a temperature not higher thanthe crystallization temperature. The semiconductor films thus obtainedhave improved uniformity for both the intra-planar distribution ofcrystallinity and the size of the constituting crystal grains. Suchsemiconductor films enable fabrication of polycrystalline silicon(abbreviated sometimes as “p-Si”, hereinafter) TFTs having uniformcharacteristics over a large-area substrate.

The crystallization of the amorphous semiconductor in vacuum or in aninactive gas atmosphere by irradiating a laser beam thereto is conductedto prevent the dangling bonds, which have once formed upon drivinghydrogen out of the amorphous semiconductor, from bonding with oxygenand hydrogen and nitrogen present in the active gas, i.e., air.

The present invention is characterized in one aspect that a large amountof dangling bonds are produced(d in the amorphous semiconductor toaccelerate crystallization of the film. This is based on the factobtained experimentally by the present inventors, which is describedbelow. It has been found that the crystallinity of an amorphous siliconfilm having subjected to a thorough driving out of hydrogen remarkablyimproves by irradiating an excimer laser light (a KrF laser emittinglight at wavelength 248 nm) to the film.

An amorphous silicon film in general contains a large amount of hydrogento neutralize the dangling bonds within the amorphous silicon film. Thepresent inventors, however, realized the important role which thedangling bonds play at the crystallization of the film from itsamorphous molten state, and therefore intentionally allowed the danglingbonds to form in the amorphous state to enhance instantaneouscrystallization from the molten state. In the course of thecrystallization taking advantage of the thus formed dangling bonds, itis very important to irradiate the laser beam in vacuum or in aninactive gas atmosphere, as mentioned earlier, because the exposure ofthe surface of the thus obtained semiconductor film to air causesbonding (neutralization) of the dangling bonds with oxygen, etc., toform an oxide film and the like on the surface of the film.

The annealing according to the process of the present invention shouldbe conducted at a temperature not higher than the crystallizationtemperature of the amorphous semiconductor. The crystallizationtemperature as referred herein signifies the temperature at which theamorphous semiconductor initiates crystallization by thermal annealing.The thermal annealing at a temperature not higher than thecrystallization temperature according to the process of the presentinvention is conducted on the basis of an experimentally derived factthat the improvement of crystallinity is hardly observed by irradiatinga laser beam to a once crystallized film, and that those crystallizedfilms are considerably low in crystallinity as compared with the filmshaving crystallized by irradiating a laser beam to films still in theiramorphous state.

It can be seen, accordingly, that it is of great importance to drive thehydrogen atoms out of the amorphous semiconductor film at a temperaturenot higher than the crystallization temperature of the amorphoussemiconductor film. However, hydrogen atoms are preferably driven out ofthe amorphous semiconductor by thermal annealing at a temperature ashigh as possible, provided that the film does not initiatecrystallization; it is of grave importance in the process according tothe present invention to form as many dangling bonds as possible in thefilm while thoroughly driving hydrogen out of the film.

The thermal annealing of the film to drive hydrogen out of the film ischaracterized by that, unlike the conventional processes which use laserbeams at a low energy density, it enables a uniform and thoroughelimination of hydrogen from the amorphous semiconductor film.

The process according to the present invention therefore is of greatadvantage concerning that it realizes a polycrystalline semiconductorfilm composed of large and uniform crystal grains.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a graph showing the relationship between the Raman spectrum ofa polycrystalline semiconductor film obtained by a process according toan embodiment of the present invention and the energy density of thelaser beam having irradiated to the film; and

FIG. 2 is a schematic drawing which shows a structure of a multi-chamberapparatus for use in EXAMPLE 2 according to an embodiment of the presentinvention.

FIG. 3 is a diagrammatic plan view of a multi-chamber system forfabricating TFTs on a substrate in accordance with an embodiment of thepresent invention.

FIGS. 4A, 4B, 4C are diagrammatic illustrations of a process formanufacturing a TFT on a substrate for an active matrix liquid crystaldevice utilizing the multi-chamber system of FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Now the present invention is explained in further detail below,referring to non-limiting examples.

EXAMPLE 1

EXAMPLE 1 shows experimentally the effect of thermal annealing ofdriving hydrogen out of an amorphous silicon film on lasercrystallization of the film (crystallization of the film by irradiatinga laser beam).

On a 1,000 Å thick silicon oxide film having deposited on a glasssubstrate as a protective film for the base film was further deposited a100 nm thick amorphous silicon (a-Si) film by a plasma CVD process underconditions as follows:

RF power: 50 W

Reaction pressure: 0.05 Torr

Reactive gas flow:

H₂=45 sccm

SiH₄=5 sccm

Substrate temperature: 300° C.

Two types of specimen were fabricated in accordance with the processabove. One was not subjected to thermal annealing, whereas the other wasthermally annealed at 500° C. for one hour in an atmosphere of aninactive gas, i.e., N₂ gas. To both of the film specimens wereirradiated a KrF excimer laser beam at a wavelength of 248 nm in vacuumto effect crystallization of the a-Si film. The laser crystallizationwas conducted in one shot, while varying the energy density of thelaser.

The substrate during the laser irradiation step was not heated in thiscase, but otherwise the laser crystallization may be conducted with thesubstrate being maintained at 500° C., i.e., the temperature of thermalannealing which had been effected prior to the laser crystallization. Itshould be noted, however, that the thermal annealing for the purpose ofdriving hydrogen out of the film need not be conducted at 500° C.Furthermore, the thermal annealing, which was effected at 500° C. for anhour in the present example, can be carried out at various temperaturesand durations, depending on the process and the semiconductor filmemployed in the individual cases.

The two types of specimens thus obtained were subjected to themeasurement of Raman spectra to study the crystallinity of bothspecimens.

In FIG. 1 are shown curve A and curve B. Curve A shows the relationshipbetween the peaks in the Raman spectra and the varying energy density ofthe laser light having irradiated for the crystallization to a specimenhaving subjected to thermal annealing (500° C., 1 hour) prior to thelaser crystallization process. Curve B relates the peaks in the Ramanspectra to the varying energy density of the laser light havingirradiated for the crystallization of a specimen not having subjected tothermal annealing prior to the laser crystallization.

Referring to FIG. 1, Curve A, it can be seen that the specimen havingsubjected to thermal annealing prior to the laser crystallization yieldsa peak at the vicinity of 521 cm⁻¹, i.e., the peak of a single crystalsilicon, and that such a thermal annealing enables formation ofcrystallized silicon having a good crystallinity even upon irradiationof a laser at a low energy, density.

In general, it is well accepted that a silicon film having crystallizedfrom amorphous silicon yields a peak in the Raman spectrum at awavenumber nearer to 521 cm⁻¹, the peak of a single crystal silicon,with increasing crystal grain diameter of the film. It can be seen fromthe fact above that the thermal annealing conducted for driving hydrogenout of the film enables formation of larger crystal grains.

Referring to Curve B, it can be seen that the crystallinity of the filmwithout thermal annealing for hydrogen elimination greatly depends onthe energy density of the laser beam having irradiated at the lasercrystallization. Furthermore, it shows that a favorable crystallinitycan be obtained only by irradiating a laser beam at a high energydensity.

It has been known that the energy density of a beam emitted from anexcimer laser apt to fluctuate; this instability in the energy densityhas long constituted a problem. However, the crystallinity is notlargely dependent on the laser beam intensity in such a case the peak ofthe Raman spectra and the energy density of the laser beam beingirradiated at the laser crystallization yield a relationshiptherebetween corresponding to Curve A; thus, a crystalline film (a p-Sifilm in the present example) having a uniform crystallinity can beobtained without being influenced by the instability of the excimerlaser.

In the case in which no thermal annealing is effected to drive hydrogenout of the film and therefore yields Curve B, a polycrystalline filmhaving a non-uniform crystallinity results by the fluctuation in theenergy density of the laser beam.

The practical fabrication process for semiconductor devices is largelyconcerned with how to obtain devices having uniform characteristics. Itcan be seen that the laser crystallization process which yield apolycrystalline film having a favorable crystallinity irrespective ofthe energy density of the laser beam having irradiated to the film,i.e., the process which yields Curve A, is useful for the practicalfabrication of semiconductor devices.

By a closer examination of FIG. 1, Curve A, it can be seen also that thespecimen having subjected to thermal treatment (thermal annealing fordriving hydrogen out of the film) initiates crystallization uponirradiation of a laser beam having a lower energy density.

It can be concluded therefrom that the lowest energy density (thresholdenergy density) to initiate the crystallization is further lowered byeffecting thermal annealing to the film for driving hydrogen out of thefilm.

Accordingly, the present inventors deduced conclusively that thethreshold energy density for the crystallization can be lowered bydriving hydrogen thoroughly out of the amorphous silicon film andthereby allowing formation of dangling bonds at a large quantity in thefilm.

EXAMPLE 2

Referring to FIG. 2, a laser crystallization process using amulti-chamber apparatus is described below. In this process, themulti-chamber apparatus is used so that an amorphous silicon film havingsubjected to thermal annealing for driving hydrogen out of the film canbe directly put to the subsequent laser crystallization step withoutonce exposing its surface to the air.

The apparatus for use in this process is shown schematically in FIG. 2.The apparatus comprises, in a serial arrangement, a plasma CVD apparatus2 for depositing amorphous silicon film for use as the starting film, athermal annealing furnace 3 to drive hydrogen out of the film, a chamber4 to effect therein laser crystallization of the film, a chamber 1 forfeeding the specimen, and a chamber 5 for discharging the specimen.Though not shown in FIG. 2, there may be established, if necessary, agas supply system to each of the chambers 1 to 5 in order to introducean active or an inactive gas, or a transportation system for transfer ofthe specimen. To each of the chambers is also provided a vacuumevacuation apparatus comprising a turbo molecular pump and a rotary pumpbeing connected in series, so that the impurity concentration,particularly the oxygen concentration, inside the chamber may bemaintained as low as possible. It is also effective to separatelyestablish a cryopump.

The multi-chamber apparatus as shown in FIG. 2 can be partitioned intothe chambers 1, 2, 3, 4 and 5 by gate valves 6. The gate valvefunctions, for example, to avoid the reactive gas inside the chamber 2,i.e., the plasma CVD apparatus, from being introduced inside the thermalannealing furnace 3 being established for driving hydrogen out of thefilm.

The chamber 3 is a thermal annealing furnace for driving hydrogen out ofthe film, in which an infrared lamp was used for the heating means. Theheating means is not restricted to the use of an infrared lamp, andother means, such as a heater, can be used in the place thereof.

The chamber 4, in which the laser annealing is effected, comprises aquartz window at the upper portion thereof. A laser beam is irradiatedto the film through this window from an exterior laser-emittingapparatus equipped with an optical system.

The laser beam is adjusted with an optical system so that the crosssection thereof may have a rectangular shape, at a predetermined widthcorresponding to that of the substrate and being elongated along adirection vertical to the direction of transporting the substrate. Inthis manner, the specimen can be continuously irradiated with the laserbeam from its edge to edge and annealed efficiently, by slowly movingthe specimen while fixing the laser system.

In the process using the apparatus shown in FIG. 2, the specimenpreferably is thermally annealed and subsequently subjected to lasercrystallization without interrupting the vacuum state. By thusconducting continuously the thermal annealing and laser crystallizationin vacuum, neutralization of the dangling bonds can be avoided and hencethe threshold energy density for the crystallization can be lowered.This provides polycrystalline silicon films composed of large-sizedgrains efficiently through the laser crystallization step.

The present process was described referring to a particular case usingan apparatus comprising chambers being connected in series. However, amodified apparatus comprises a plurality of chambers for each step inaccordance with the process duration of the specimen within eachchamber. Furthermore, modifications may be made on the apparatus so thatthe chambers are each provided with a common room for supplying thespecimen. The productivity can be improved by employing such anarrangement in which a plurality of treatments can be proceededsimultaneously by taking advantage of time difference.

The apparatus hereinbefore was described in connection with a process ofdepositing a film by plasma CVD. However, the film deposition may becarried out by other processes such as sputtering and thermal CVD;moreover, for example, a film deposition apparatus for depositing aninsulating film therein may be further connected to the multi-chamberapparatus above, depending on the desired sequence for fabricating afilm.

Conclusively, the present invention provides process which comprises athermal annealing of an amorphous semiconductor film at a temperaturenot higher than the crystallization temperature of the film in vacuum orin an inactive gas atmosphere, followed by crystallization of the filmin vacuum or in an inactive gas atmosphere by irradiating a laser beamto the film. The process provides a uniform polycrystalline silicon filmhaving high crystallinity, which, has less dependence on the energydensity of the laser beam which is irradiated thereto forcrystallization.

While the invention has been described in detail and with reference tospecific embodiments thereof, it will be apparent to one skilled in theart that various changes and modifications can be made therein withoutdeparting from the spirit and scope thereof.

The following is an additional description explaining another embodimentof the present invention.

A multi-chamber system for fabricating TFTs on a substrate is shown inFIG. 3. The multi-chamber system utilized in this embodiment is amodification of the system shown in FIG. 2. While the chambers areserially connected in one line in the system of FIG. 2, a plurality ofchambers are connected with one another through one common chamber inthe present embodiment, as referred to hereinbefore.

Referring to FIG. 3, the system comprises loading and unloading chambers12 and 11, a plasma CVD chamber 13 for forming an amorphous silicon, aheat treatment chamber 14, a sputtering chamber 15 for forming a siliconoxide and a laser processing chamber 16. These chambers are connectedwith a common chamber (transfer chamber) 17 through gate valves 20-25,respectively. Also, a robot 18 is provided in the common chamber fortransferring a substrate between the chambers. Further, although notshown in the figure, each chamber including the common chamber may beprovided with its own vacuum pump. Accordingly, each process chamber canbe operated completely isolated from one another.

The manufacture of a TFT on a substrate 19 for an active matrix liquidcrystal device will be described below in connection with FIG. 3 andFIGS. 4A-4C.

Initially, after the loading chamber 12 is loaded with a glass substratesuch as Corning 7059 glass and is pumped down, the gate valve 21 isopened and allows access to the substrate by the robot 18.

The robot 18 transfers it into the plasma CVD chamber 13 through thetransfer chamber 17.

After the chamber 13 is loaded with the substrate and the gate valve 22is closed, the chamber 13 is pumped down and the CVD formation of theamorphous silicon film is started. An example of the process parametersis as below:

Starting gas: SiH₄ diluted with hydrogen

substrate temperature: 250° C.

film thickness: 300 Å

Power: 13.56 MHz r.f. power

Then, in the same manner, the substrate 19 is transferred from thechamber 13 to the heat treatment chamber 14 by the robot 18. Thesubstrate 19 having the amorphous silicon 31 is heated at 500° C. forone hour in N₂ gas. Thereby, hydrogen can be discharged from theamorphous silicon film 31.

The substrate is then transferred from the chamber 14 to the sputteringchamber 15. In the chamber 15, a silicon oxide film 32 is deposited onthe amorphous silicon film 31 to form a protective layer for thesubsequent laser annealing. The process parameters may be as below:

target: artificial quartz

sputtering gas: Ar 25%—O₂ 75%

substrate temperature: 100° C.

power: 13.56 MHz, 400 W

film thickness: 100 nm

After the formation of the silicon oxide layer 32, the substrate is thentransferred to the laser processing chamber 16 by the robot 18. Thechamber 16 is provided with a quartz window 27 through which a laserlight is emitted into the inside of the chamber 16 from a KrF excimerlaser 26 located outside the chamber 16. In the chamber 16, a lasercrystallization of the amorphous silicon film 31 is performed in anoxygen gas. The condition of the laser annealing is shown below:

energy density: 350 mJ/cm²

pulse number: 1-10 shots

substrate temperature: 400° C.

Thus, the amorphous silicon is crystallized. The substrate after thecrystallization is removed from the multi-chamber system through theunloading chamber 11.

After patterning the polycrystalline silicon film 31 into an island formand removing the upper protective silicon oxide layer 32 by knownetching, another silicon oxide layer 33 is formed on the silicon layer31 through an r.f. plasma CVD using TEOS and oxygen to a thickness of1000 Å.

Then, a gate electrode 34 is formed on the silicon oxide layer 34 bydepositing a aluminum layer doped with silicon to a thickness of 6000 Åand pattering it. (FIG. 4B)

Then, as shown in FIG. 4B, a dopant impurity such as phosphorous orboron is doped in the silicon layer 31 by a plasma doping with the gateelectrode as a mask. The dose is 1×10¹⁵-4×10¹⁵ atoms/cm².

Subsequently, the dopant is activated by using a KrF excimer laser asshown in FIG. 4C. The laser annealing is performed at an energy density200-350 mJ/cm², at 300-500° C. substrate temperature.

Thus, a TFT is manufactured on the substrate.

While the figure shows only one TFT, it is obvious that a number of TFTsare manufactured at the same time through the same process. Also, it isadvantageous to form a silicide oxide layer on the glass substrate priorto the formation of the amorphous silicon layer. This can be done in thesputtering chamber 15.

What is claimed is:
 1. A method for manufacturing a semiconductor devicecomprising the steps of: preparing a multi-chamber system having atleast a first chamber for heating a semiconductor film formed over asubstrate and a second chamber for irradiating a laser light having arectangular cross section elongated in one direction to saidsemiconductor film; introducing said substrate to said first chamber;heating said semiconductor film over said substrate by using an infraredlamp in said first chamber; transferring said substrate second chamberwithout exposing said substrate to the air after heating saidsemiconductor film; and irradiating said laser to said semiconductorfilm to crystallize said semiconductor film in said second chamber,while moving said substrate relatively to said laser light in adirection orthogonal to the elongated direction of said rectangularcross section.
 2. A method according to claim 1, wherein saidsemiconductor film is formed over said substrate before introducing saidsubstrate to said first chamber by a method selected from the groupconsisting of a plasma CVD method, a thermal CVD method and a sputteringmethod.
 3. A method according to claim 1, wherein the heating step isperformed in a vacuum or in an inactive atmosphere.
 4. A methodaccording to claim 1, wherein said laser light is an excimer laser.
 5. Amethod according to claim 1, wherein the transferring step is performedthough a common chamber.
 6. A method for manufacturing a semiconductordevice comprising the steps of: preparing a multi-chamber system havingat least a first chamber for heating a semiconductor film formed over asubstrate and a second chamber for irradiating a laser light having arectangular cross section elongated in one direction to saidsemiconductor film; introducing said substrate to said first chamber;heating said semiconductor film over said substrate in said firstchamber to reduce a concentration of hydrogen therein; transferring saidsubstrate to said second chamber without exposing said substrate to theair after heating said semiconductor film; and irradiating said laserlight to said semiconductor film to crystallize said semiconductor filmin said second chamber, while moving said substrate relatively to saidlaser light in a direction orthogonal to the elongated direction of saidrectangular cross section.
 7. A method according to claim 6, whereinsaid semiconductor film is formed over said substrate before introducingsaid substrate to said first chamber by a method selected from the groupconsisting of a plasma CVD method, a thermal CVD method and a sputteringmethod.
 8. A method according to claim 6, wherein the heating step isperformed in a vacuum or in an inactive atmosphere.
 9. A methodaccording to claim 6, wherein said laser light is an excimer laser. 10.A method according to claim 6, wherein the transferring step isperformed through a common chamber.
 11. A method for manufacturing asemiconductor device comprising the steps of: preparing a multi-chambersystem having at least a first chamber for heating a semiconductor filmcomprising amorphous silicon formed over a substrate and a secondchamber for irradiating a laser light having a rectangular cross sectionelongated in one direction to said semiconductor film; introducing saidsubstrate to said first chamber; heating said semiconductor film oversaid substrate at a temperature not higher than a crystallizationtemperature of said amorphous silicon by using an infrared lamp in saidfirst chamber; transferring said substrate to said second chamberwithout exposing said substrate to the air after heating saidsemiconductor film; and irradiating said laser light to saidsemiconductor film to crystallize said semiconductor film in said secondchamber, while moving said substrate relatively to said laser light in adirection orthogonal to the elongated direction of said rectangularcross section.
 12. A method according to claim 11, wherein saidsemiconductor film is formed over said substrate before introducing saidsubstrate to said first chamber by a method selected from the groupconsisting of a plasma CVD method, a thermal CVD method and a sputteringmethod.
 13. A method according to claim 11, wherein the heating step isperformed in a vacuum or in an inactive atmosphere.
 14. A methodaccording to claim 11, wherein said laser light is an excimer laser. 15.A method according to claim 11, wherein the transferring step isperformed through a common chamber.
 16. A method for manufacturing asemiconductor device comprising the steps of: preparing a multi-chambersystem having at least a first chamber for heating a semiconductor filmformed over a substrate and a second chamber for irradiating a laserlight having a rectangular cross section elongated in one direction tosaid semiconductor film; introducing said substrate to said firstchamber; heating said semiconductor film over substrate at a temperaturenot higher than a crystallization temperature of said amorphous siliconin said first chamber to reduce a concentration of hydrogen therein;transferring said substrate to said second chamber without exposing saidsubstrate to the air after heating said semiconductor film; andirradiating said laser light to said semiconductor film to crystallizesaid semiconductor film in said second chamber, while moving saidsubstrate relatively to said laser light in a direction orthogonal tothe elongated direction of said rectangular cross section.
 17. A methodaccording to claim 16, wherein said semiconductor film is formed oversaid substrate before introducing said substrate to said first chamberby a method selected from the group consisting of a plasma CVD method, athermal CVD method and a sputtering method.
 18. A method according toclaim 16, wherein the heating step is preformed in a vacuum or in aninactive atmosphere.
 19. A method according to claim 16, wherein saidlaser light is an excimer laser.
 20. A method according to claim 16,wherein the transferring step is preformed through a common chamber. 21.A method for manufacturing a semiconductor device comprising the stepsof: preparing a multi-chamber system having at least a first chamber forforming a semiconductor film formed over a substrate and a secondchamber for irradiating a laser light having a rectangular cross sectionelongated in one direction to said semiconductor film; forming saidsemiconductor film over said substrate in said first chamber;transferring said substrate to said second chamber without exposing saidsubstrate to the air after forming said semiconductor film; andirradiating said laser light to said semiconductor film to crystallizesaid semiconductor film in said second chamber, while moving saidsubstrate relatively to said laser light in a direction orthogonal tothe elongated direction of said rectangular cross section.
 22. A methodaccording to claim 21, wherein said semiconductor film is formed oversaid substrate by a method selected from the group consisting of aplasma CVD method, a thermal CVD method and a sputtering method.
 23. Amethod according to claim 21 further comprising a heating step in avacuum or in an inactive atmosphere before irradiating said laser light.24. A method according to claim 21, wherein said laser light is anexcimer laser.
 25. A method according to claim 21, wherein thetransferring step is preformed through a common chamber.
 26. A methodfor manufacturing a semiconductor device comprising the steps of:preparing a multi-chamber system having at least a first for forming asemiconductor film, a second chamber for heating said semiconductor filmand a third chamber for irradiating a laser light having a rectangularcross section elongated in one direction to said semiconductor film;forming said semiconductor film over a substrate in said first chamber;transferring said substrate to said second chamber without exposing saidsubstrate to the air after forming said semiconductor film; heating saidsemiconductor film over said substrate by using an infrared lamp in saidsecond chamber; transferring said substrate to said third chamberwithout exposing said substrate to the air after heating saidsemiconductor film; and irradiating said laser light to saidsemiconductor film to crystallize said semiconductor film in said thirdchamber, while moving said substrate relatively to said laser light in adirection orthogonal to the elongated direction of said rectangularcross section.
 27. A method according to claim 26, wherein saidsemiconductor film is formed in said first chamber by a method selectedfrom the group consisting of a plasma CVD method, a thermal CVD methodand a sputtering method.
 28. A method according to claim 26, wherein theheating step is performed in a vacuum or in an inactive atmosphere. 29.A method according to claim 26, wherein said laser light is an excimerlaser.
 30. A method according to claim 26, wherein each of transferringsteps is performed through a common chamber.
 31. A method formanufacturing a semiconductor device comprising the steps of: preparinga multi-chamber system having at least a first for forming asemiconductor film, a second chamber for heating said semiconductor filmand a third chamber for irradiating a laser light having a rectangularcross section elongated in one direction to said semiconductor film;forming said semiconductor film over a substrate in said first chamber;transferring said substrate to said second chamber without exposing saidsubstrate to the air after forming said semiconductor film; heating saidsemiconductor film over said substrate in said second chamber to reducea concentration of hydrogen therein; transferring said substrate to saidthird chamber without exposing said substrate to the air after heatingsaid semiconductor film; and irradiating said laser light to saidsemiconductor film in said third chamber to crystallize saidsemiconductor film, while moving said substrates relatively to saidlaser light in direction ortogonal to the elongated direction of saidrectangular cross section.
 32. A method according to claim 31, whereinsaid semiconductor film if formed in said first chamber by a methodselected from the group consisting of a plasma CVD method, a thermal CVDmethod and a sputtering method.
 33. A method according to claim 31,wherein the heating step is performed in a vacuum or in an inactiveatmosphere.
 34. A method according to claim 31, wherein said laser lightis an excimer laser.
 35. A method according to claim 31, wherein each oftransferring steps is performed through a common chamber.
 36. A methodfor manufacturing a semiconductor device comprising the steps of:preparing a multi-chamber system having at least a first chamber forheating a semiconductor film formed over a substrate and a secondchamber for irradiating a laser light having a rectangular cross sectionelongated in one direction to said semiconductor film; introducing saidsubstrate to said first chamber; heating said semiconductor film oversaid substrate in said first chamber; transferring said substrate tosaid second chamber without exposing said substrate to the air afterheating said semiconductor film; and irradiating said laser light tosaid semiconductor film to crystallize said semiconductor film in saidsecond chamber, while moving said substrate relatively to said laserlight in a direction orthogonal to the elongated direction of saidrectangular cross section.
 37. A method according to claim 36, whereinsaid semiconductor film is formed over said substrate before introducingsaid substrate to said first chamber by a method selected from the groupconsisting of a plasma CVD method, a thermal CVD method and a sputteringmethod.
 38. A method according to claim 36, wherein the heating step isperformed in a vacuum or in an inactive atmosphere.
 39. A methodaccording to claim 36, wherein said laser light is an excimer laser. 40.A method according to claim 36, wherein the transferring step isperformed though a common chamber.
 41. A method for manufacturing asemiconductor device comprising the steps of: introducing a substrate toa first chamber of a multi-chamber system; heating a semiconductor filmover said substrate by using an infrared lamp in said first chamber;transferring said substrate to a second chamber of said multi-chambersystem without exposing said substrate to the air after heating saidsemiconductor film; and irradiating a laser light to said semiconductorfilm to crystallize said semiconductor film in said second chamber,while moving said substrate relatively to said laser light in adirection orthologonal to an elongated direction of said laser light.42. A method according to claim 41, wherein said semiconductor film isformed over said substrate before introducing said substrate to saidfirst chamber by a method selected from the group consisting of a plasmaCVD method, a thermal CVD method and a sputtering method.
 43. A methodaccording to claim 41, wherein the heating step is performed in a vacuumor in an inactive atmosphere.
 44. A method according to claim 41,wherein said laser light is an excimer laser.
 45. A method according toclaim 41, wherein the transferring step is performed through a commonchamber.
 46. A method for manufacturing a semiconductor devicecomprising the steps of: introducing a substrate to a first chamber of amulti-chamber system; heating a semiconductor film over said substratein said first chamber to reduce a concentration of hydrogen therein.transferring said substrate to a second chamber of said multi-chambersystem without exposing said substrate to the air after heating saidsemiconductor film; and irradiating a laser light to said semiconductorfilm to crystallize said semiconductor film in said second chamber,while moving said substrate relatively to said laser light in adirection orthogonal to an elongated direction of said laser light. 47.A method according to claim 46, wherein said semiconductor film isformed over said substrate before introducing said substrate to saidfirst chamber by a method selected from the group consisting of a plasmaCVD method, a thermal CVD method and a sputtering method.
 48. A methodaccording to claim 46, wherein the heating step is performed in a vacuumor in an inactive atmosphere.
 49. A method according to claim 46,wherein said laser light is an excimer laser.
 50. A method according toclaim 46, wherein the transferring step is performed through a commonchamber.
 51. A method for manufacturing a semiconductor devicecomprising the steps of: introducing a substrate to a first chamber of amulti-chamber system; heating a semiconductor film over said substrateat a temperature not higher than a crystallization temperature of saidamorphous silicon by using an infrared lamp in said first chamber;transferring said substrate to a second chamber of said multi-chambersystem without exposing said substrate to the air after heating saidsemiconductor film; and irradiating a laser light to said semiconductorfilm to crystallize said semiconductor film in said second chamber,while moving said substrate relatively to said laser light in adirection orthogonal to an elongated direction of said laser light. 52.A method according to claim 51, wherein said semiconductor film isformed over said substrate before introducing said substrate to saidfirst chamber by a method selected from the group consisting of a plasmaCVD method, a thermal CVD method and a sputtering method.
 53. A methodaccording to claim 51, wherein the heating step is performed in a vacuumor in an inactive atmosphere.
 54. A method according to claim 51,wherein said laser light is an excimer laser.
 55. A method according toclaim 51, wherein the transferring step is performed though a commonchamber.
 56. A method for manufacturing a semiconductor devicecomprising the steps of: introducing a substrate to a first chamber ofsaid multi-chamber system; heating a semiconductor film over saidsubstrate at a temperature not higher than a crystallization temperatureof said amorphous silicon in said first chamber to reduce aconcentration of hydrogen therein; transferring said substrate to asecond chamber of said multi-chamber system without exposing saidsubstrate to the air after heating said semiconductor film; andirradiating a laser light to said semiconductor film to crystallize saidsemiconductor film in said second chamber, while moving said substraterelatively to said laser light in a direction orthogonal to an elongateddirection of said laser light.
 57. A method according to claim 56,wherein said semiconductor film is formed over said substrate beforeintroducing said substrate to said first chamber by a method selectedfrom the group consisting of a plasma CVD method, a thermal CVD methodand a sputtering method.
 58. A method according to claim 56, wherein theheating step is performed in a vacuum or in an inactive atmosphere. 59.A method according to claim 56, wherein said laser light is an excimerlaser.
 60. A method according to claim 56, wherein the transferring stepis performed though a common chamber.